CN106131946B

CN106131946B - Method and apparatus for calculating power headroom in wireless communication system

Info

Publication number: CN106131946B
Application number: CN201610579924.0A
Authority: CN
Inventors: 金成勋; 郑景仁; 金相范; G-J.范利肖特
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2010-11-05
Filing date: 2011-11-04
Publication date: 2019-12-13
Anticipated expiration: 2031-11-04
Also published as: CN103190102A; EP4152679A1; KR101910899B1; CN103190103B; EP2636171A2; JP2013545397A; KR20120048491A; CN103190103A; KR20190021303A; CN103190102B; JP6046042B2; WO2012060660A3; KR102051510B1; KR101954185B1; EP3748894A1; EP2636171B1; WO2012060659A3; WO2012060660A2; JP2018023160A; JP6325636B2

Abstract

A method and apparatus for calculating a power headroom in a wireless communication system are provided. The method comprises the following steps: determining whether the terminal transmits a Physical Uplink Shared Channel (PUSCH) in a subframe for a serving cell; calculating a maximum uplink transmission power based on the determination; and calculating a power headroom for the serving cell based on the calculated maximum uplink transmission power, wherein if the terminal does not transmit a PUSCH in the subframe for the serving cell, the maximum uplink transmission power is calculated based on at least one of a cell-specific maximum allowed transmission power and a terminal-specific maximum allowed transmission power without using a backoff parameter.

Description

Method and apparatus for calculating power headroom in wireless communication system

The present application is a divisional application of an invention patent application with an application date (international application date) of 2011, 11/4, an application number of 201180053216.9 (international application number of PCT/KR2011/008380), entitled "method and apparatus for calculating a power headroom in a carrier aggregation mobile communication system".

Technical Field

The invention relates to a power headroom (power headroom) calculation method and a device. More particularly, the present invention relates to a method and an apparatus for calculating a power headroom of a User Equipment (UE) of a primary cell (primary cell) in a Long Term Evolution-Advanced (LTE-a) mobile communication system.

Background

Mobile communication systems have been developed to provide subscribers with voice communication services on the move. With the rapid advance of technology, mobile communication systems have been developed to support high-speed data communication services as well as standard voice communication services.

recently, Long Term Evolution (LTE) has been developed as a next Generation mobile communication system of the third Generation Partnership Project (3 GPP). The LTE system that has been commercialized around 2010 is a technology for realizing high-speed packet-based communication of about 100 Mbps. With regard to commercialization of the LTE system, discussion is being made on several schemes, such as one scheme for reducing the number of nodes located in a communication path by simplifying a network configuration and another scheme for bringing a wireless protocol close to a wireless channel to the maximum extent.

Unlike voice services, data services are characterized in that resources are allocated according to the amount of data to be transmitted and channel conditions. Accordingly, in a wireless communication system such as a cellular communication system, a scheduler manages resource allocation in consideration of an amount of resources, channel conditions, and an amount of data. This is also the case in the LTE system, which is one of the next-generation mobile communication systems, so that a scheduler located in the base station manages and allocates radio resources.

Recently, the evolution of an LTE-Advanced (LTE-a) system as an LTE system having a new technology for increasing a data rate has been actively discussed. Carrier Aggregation (CA) is a technology that has been newly adopted in LTE-a systems. Unlike data communication according to the related art in which a User Equipment (UE) uses a single uplink carrier and a single downlink carrier, CA enables the UE to use a plurality of uplink and/or downlink carriers.

disclosure of Invention

Technical problem

Since the uplink transmission power determination algorithm according to the related art is designed for a UE operating with one uplink carrier and one downlink carrier, it is difficult to apply the transmission power determination procedure according to the related art to the uplink transmission power determination of a UE supporting CA. More particularly, there is a need for a procedure and method for reporting Power Headroom (PH) of a CA-capable UE.

Technical scheme

Aspects of the present invention address at least the above problems and/or disadvantages and provide at least the advantages described below. Accordingly, an aspect of the present invention is to provide a method and apparatus for efficiently reporting a Power Headroom (PH) of a UE in a mobile communication system supporting carrier aggregation. An aspect of the present invention is to provide a Power Headroom (PH) calculation method and apparatus of a User Equipment (UE) capable of calculating a PH more efficiently.

According to an aspect of the present invention, there is provided a method of calculating a PH of a terminal in a mobile communication system supporting aggregation of a plurality of serving cells. The method includes determining whether the terminal transmits at least one of uplink data and uplink control signals in an active serving cell; and calculating a PH of the activated serving cell according to whether the terminal transmits at least one of uplink data and uplink control signals in the activated serving cell.

According to another aspect of the present invention, there is provided an apparatus for calculating a PH of a terminal in a mobile communication system supporting aggregation of a plurality of serving cells. The apparatus includes a controller for determining whether the terminal transmits at least one of uplink data and uplink control signals in an active serving cell; and a calculator for calculating a PH of the activated serving cell according to whether the terminal transmits at least one of uplink data and uplink control signals in the activated serving cell.

According to another aspect of the present invention, there is provided a method of receiving a PH of a base station in a mobile communication system supporting aggregation of a plurality of serving cells. The method includes receiving an extended PH report (PHR) from a terminal; and determining a PH of the activated serving cell by analyzing the extended PHR, wherein the terminal calculates the PH of the activated serving cell according to whether the terminal transmits at least one of uplink data and uplink control signals in the activated serving cell.

According to another aspect of the present invention, there is provided an apparatus for receiving a PH of a base station in a mobile communication system supporting aggregation of a plurality of serving cells. The apparatus includes a receiver for receiving an extended PHR transmitted by a terminal; and a controller for determining a PH of the activated serving cell by analyzing the extended PHR, wherein the terminal calculates the PH of the activated serving cell according to whether the terminal transmits at least one of uplink data and uplink control signals in the activated serving cell.

According to another aspect of the present invention, there is provided a method for calculating a power headroom of a terminal in a wireless communication system, the method comprising: determining whether the terminal transmits a Physical Uplink Shared Channel (PUSCH) in a subframe for a serving cell; calculating a maximum uplink transmission power based on the determination; and calculating a power headroom for the serving cell based on the calculated maximum uplink transmission power, wherein if the terminal does not transmit a PUSCH in the subframe for the serving cell, the maximum uplink transmission power is calculated based on at least one of a cell-specific maximum allowed transmission power and a terminal-specific maximum allowed transmission power without using a backoff parameter.

according to another aspect of the present invention, there is provided a terminal for calculating a power headroom in a wireless communication system, the terminal comprising: a transceiver configured to transmit and receive signals; and a controller configured to: determining whether the terminal transmits a Physical Uplink Shared Channel (PUSCH) in a subframe for a serving cell, calculating a maximum uplink transmission power based on the determination, and calculating a power headroom for the serving cell based on the calculated maximum uplink transmission power, wherein if the terminal does not transmit a PUSCH in the subframe for the serving cell, the maximum uplink transmission power is calculated based on at least one of a cell-specific maximum allowed transmission power and a terminal-specific maximum allowed transmission power without using a backoff parameter.

According to another aspect of the present invention, there is provided a method for receiving a power headroom by a base station in a wireless communication system, the method comprising: receiving an extended power headroom report from a terminal; and identifying a power headroom for a serving cell based on the extended power headroom report, wherein the power headroom for the serving cell is calculated based on a maximum uplink transmission power calculated according to whether the terminal transmits a Physical Uplink Shared Channel (PUSCH) in a subframe for the serving cell, and wherein, if the terminal does not transmit a PUSCH in the subframe for the serving cell, the maximum uplink transmission power is calculated based on at least one of a cell-specific maximum allowed transmission power and a terminal-specific maximum allowed transmission power without using a backoff parameter.

According to another aspect of the present invention, there is provided a base station for receiving a power headroom in a wireless communication system, the base station comprising: a transceiver configured to transmit and receive signals; and a controller configured to: receiving an extended power headroom report from a terminal, and identifying a power headroom for a serving cell based on the extended power headroom report, wherein the power headroom for the serving cell is calculated based on a maximum uplink transmission power calculated according to whether the terminal transmits a Physical Uplink Shared Channel (PUSCH) in a subframe for the serving cell, and wherein, if the terminal does not transmit a PUSCH in the subframe for the serving cell, the maximum uplink transmission power is calculated based on at least one of a cell-specific maximum allowed transmission power and a terminal-specific maximum allowed transmission power without using a backoff parameter.

Other aspects, advantages and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

Advantageous effects

According to the present invention, the PH calculation method and apparatus can calculate the PH of an active serving cell by considering whether the active serving cell has uplink transmission data and/or uplink control signals to be transmitted, thereby more efficiently determining the PH of each active serving cell.

Drawings

The above and other aspects, features and advantages of certain exemplary embodiments of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a diagram illustrating a mobile communication system according to an exemplary embodiment of the present invention;

Fig. 2 is a diagram illustrating a protocol stack of a mobile communication system according to an exemplary embodiment of the present invention;

Fig. 3 is a diagram illustrating Carrier Aggregation (CA) in a mobile communication system according to an exemplary embodiment of the present invention;

Fig. 4 illustrates a principle of a CA used in a mobile communication system according to an exemplary embodiment of the present invention;

Fig. 5 is a diagram illustrating a Power Headroom (PH) report according to an exemplary embodiment of the present invention;

Fig. 6 is a diagram illustrating resource allocation for transmission of only a Physical Uplink Shared Channel (PUSCH) and simultaneous transmission of a PUSCH and a Physical Uplink Control Channel (PUCCH) according to an exemplary embodiment of the present invention;

Fig. 7 is a flowchart illustrating a PH report (PHR) transmission procedure according to an exemplary embodiment of the present invention; and

Fig. 8 is a block diagram illustrating a User Equipment (UE) according to an exemplary embodiment of the present invention.

It should be noted that throughout the drawings, the same reference numerals are used to describe the same or similar elements, features and structures.

Detailed Description

The following description with reference to the accompanying drawings is provided to facilitate a thorough understanding of exemplary embodiments of the present invention defined by the claims and equivalents thereof. The description includes various specific details to facilitate understanding, but these specific details should only be considered exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. Moreover, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

the terms and expressions used in the following description and claims are not limited to their dictionary meanings but are used only by the inventor to enable a clear and consistent understanding of the present invention. Accordingly, it should be apparent to those skilled in the art that the following description of the exemplary embodiments of the present invention are provided for illustration only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

It should be understood that the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component surface" includes reference to one or more of such surfaces.

Exemplary embodiments of the present invention provide a Power Headroom (PH) calculation method and apparatus for a User Equipment (UE) of a Primary Cell (PCell) in a long term evolution-advanced (LTE-a) mobile communication system.

Unlike the method according to the related art in which only one of a Physical Uplink Shared Channel (PUSCH) and a Physical Uplink Control Channel (PUCCH) can be transmitted during a preset period, the LTE-a mobile communication system can simultaneously transmit the PUSCH and the PUCCH in the uplink. Therefore, it is necessary to calculate the PH differently according to whether the PUSCH is transmitted together with the PUCCH or only the PUSCH is transmitted. Exemplary embodiments of the present invention provide an efficient PH calculation method when PUSCH and PUCCH are simultaneously transmitted.

Before explaining the present invention, a mobile communication system to which exemplary embodiments of the present invention are applied is described with reference to fig. 1, 2, and 3. In the following, a case for an LTE system is described.

fig. 1 is a diagram illustrating a mobile communication system according to an exemplary embodiment of the present invention.

Referring to fig. 1, a radio access network of a mobile communication system includes evolved node bs (enbs) 105, 110, 115, and 120, a Mobility Management Entity (MME) 125, and a Serving-Gateway (S-GW) 130. The UE 135 connects to an external network via the enbs 105, 110, 115 and 120 and the S-GW 130.

The enbs 105, 110, 115 and 120 correspond to legacy node bs of a Universal Mobile Communications System (UMTS). The enbs 105, 110, 115 and 120 allow UEs to establish radio links and are responsible for complex functions compared to legacy node bs. In the LTE system, all user traffic, including real-time services such as Voice over Internet Protocol (VoIP), is provided through a shared channel, and thus a device located in an eNB is required to schedule data based on state information of a UE. To achieve data rates up to 100Mbps, the LTE system employs Orthogonal Frequency Division Multiplexing (OFDM) as a radio access technology. In addition, the LTE system employs Adaptive Modulation and Coding (AMC) to determine a Modulation scheme and a channel Coding rate suitable for channel conditions of the UE. S-GW130 is an entity that provides data bearers (bearer) for establishing and releasing data bearers under the control of MME 125. The MME125 is responsible for various control functions and is connected to multiple enbs 105, 110, 115 and 120.

Fig. 2 is a diagram illustrating a protocol stack of a mobile communication system according to an exemplary embodiment of the present invention.

referring to fig. 2, a Protocol stack of the LTE system includes Packet Data Convergence Protocol (PDCP) layers 205 and 240, Radio Link Control (RLC) layers 210 and 235, Medium Access Control (MAC) layers 215 and 230, and Physical (PHY) layers 220 and 225. The PDCP layers 205 and 240 are responsible for Internet Protocol (IP) header (header) compression/decompression. The RLC layers 210 and 235 are responsible for segmenting PDCP Protocol Data Units (PDUs) into segments with a size suitable for Automatic Repeat Request (ARQ) operations. The MAC layers 215 and 230 are responsible for establishing connections to a plurality of RLC entities in order to multiplex and demultiplex RLC PDUs into RLC PDUs. The PHY layers 220 and 225 perform channel coding on the MAC PDU and modulate the MAC PDU into OFDM symbols for transmission over a wireless channel, or perform demodulation and channel decoding on received OFDM symbols and deliver the decoded data to higher layers. From a transport point of view, Data input to a protocol entity is called a Service Data Unit (SDU) and Data output by the protocol entity is called a Protocol Data Unit (PDU).

carrier Aggregation (CA) is described below with reference to fig. 3.

Fig. 3 is a diagram illustrating a CA in a mobile communication system according to an exemplary embodiment of the present invention.

Referring to fig. 3, an eNB can use a plurality of carriers transmitted and received in different frequency bands. For example, the eNB 305 can be configured to use a carrier 315 having a center frequency f1 and a carrier 310 having a center frequency f 3. If CA is not supported, the UE 330 must transmit/receive a data unit of one of the carriers 310 and 315. However, the CA capable UE 330 is able to transmit/receive data using both carriers 310 and 315. The eNB can increase the amount of resources to be allocated to the CA-capable UE to suit the channel condition of the UE, thereby increasing the data rate of the UE. In the case where a cell is configured with one downlink carrier and one uplink carrier, CA may be understood as if a UE communicates data via a plurality of cells according to the related art concept. By using CA, the maximum data rate increases in proportion to the number of aggregated carriers. Configuring the aggregated carriers via Radio Resource Control (RRC) signaling. In the LTE system, carriers may be added to or removed from the CA using an RRC connection reconfiguration (RRCConnectionReconfiguration) message. Although a specific carrier is configured, data transmission is not performed. In order to use the corresponding carrier, the carrier must be activated through Medium Access Control (MAC) signaling. In the LTE system, configured carriers are activated through a MAC Control Element (CE) in a MAC PDU. Since the service is provided through a plurality of activated carriers, there are a plurality of serving cells.

At the same time, the uplink transmission power may be kept below a suitable level in order to mitigate interference. For this purpose, the UE determines an uplink transmission power using a preset function and performs uplink transmission at the determined uplink transmission power. For example, the UE determines a required uplink transmission power value by inputting input values such as scheduling information including an amount of resources allocated to the UE, a Modulation and Coding Scheme (MCS), and information required to estimate channel conditions such as path loss, and performs uplink transmission by applying the determined uplink transmission power value. The available uplink transmission power value of the UE is limited to a maximum transmission power value of the UE such that the UE performs uplink transmission at the maximum transmission power value when the determined transmission power value exceeds the maximum transmission power value. In this case, the uplink transmission power is insufficient, resulting in degradation of the uplink transmission quality. Accordingly, the eNB may perform scheduling such that the required transmission power does not exceed the maximum transmission power. However, since several parameters such as path loss cannot be verified by the eNB, the UE must report its PH value to the eNB by means of a PH report (PHR).

There are several factors that affect PH, such as: 1) the amount of allocated transmission resources, 2) the MCS to be applied to the uplink transmission, 3) the Path Loss (Path Loss, PL) of the associated downlink carrier, and 4) the value of the accumulated transmission power control command. Among these factors, the PL and the accumulated transmission power control command value are variable according to uplink carriers, so that when a plurality of uplink carriers are aggregated, transmission of the PHR can be configured per carrier. However, in order to efficiently transmit PHR, it may be advantageous to report the PHs of all uplink carriers on one uplink carrier. Depending on the management policy, it may be necessary to transmit the PH of the carrier on which no PUSCH transmission actually occurs. In this case, it is possible to more efficiently report PHs of a plurality of uplink carriers on a single uplink carrier. For this purpose, the PHR according to the related art must be extended. The plurality of PHs carried by the PHR may be arranged in a preset order.

Fig. 4 illustrates a principle of CA used in mobile communication according to an exemplary embodiment of the present invention.

referring to fig. 4, five downlink carriers may be aggregated for a UE, including: downlink carrier 1405, downlink carrier 2410, downlink carrier 3415, downlink carrier 4420, and downlink carrier 5425. Similarly, five uplink carriers may be aggregated for the UE, including: uplink carrier 1430, uplink carrier 2435, uplink carrier 3440, uplink carrier 4445, and uplink carrier 5450. Here, one of the aggregated carriers may be selected to transmit the PHs of 5 uplink carriers. For example, when aggregating three uplink carriers 440, 445, and 450 for the UE, the PHR may be configured to carry PHs of the three uplink carriers.

The PHR is triggered when a path loss of the connected downlink carrier is equal to or greater than a preset threshold, or when a PHR time is prohibited from expiring, or when a preset time period has elapsed after PHR generation. Once the PHR is triggered, the UE waits until a time available for uplink transmission (e.g., a time at which uplink transmission resources are allocated) arrives, instead of immediately transmitting the PHR. This is because the PHR is not very delay sensitive information. The UE transmits the PHR in a first uplink transmission. The PHR is MAC layer control information and has a length of 8 bits. The first two bits of the PHR are reserved for future use, while the remaining 6 bits are used to indicate a value ranging between-23 dB and 40dB as the PH of the UE. The UE calculates the PH using the following equation.

Equation 1

PH(i)＝P_CMAX，c(i)-{10log₁₀(M_PUSCH，c(i))+P_{O_PUSCH，C}(J)+α_c(j)·PL_c+Δ_TF，c(i)+f_c(i)}

Using maximum uplink transmission power P_CMAX,c(i) Number of resource blocks M_PUSCH,c(i) power offset Δ from MCS_TF,cpath loss PL_cand an accumulated Transmit Power Control (TPC) command f_c(i) to determine PH (i) of the ith subframe in the serving cell c. In equation 1, PL_cIndicating the path loss of the cell providing information about the path loss in the serving cell c. Uplink transmission for determining a serving cellThe path loss of the transmission power is a path loss of a downlink channel of the corresponding cell or a path loss of a downlink channel of another cell. The cell whose path loss is to be used is selected by the eNB and notified to the UE in the call setup procedure. In equation 1, f_c(i) Is the accumulated value of the accumulated Transmit Power Control (TPC) commands for the serving cell c. Parameter P_{O_PUSCH,c}Represents a higher layer parameter corresponding to the sum of the cell-specific value and the UE-specific value. In general, P_{O_PUSCH,c}Is set to a value determined depending on a transmission type of the PUSCH such as semi-persistent (semi-persistent) scheduling, dynamic scheduling, and random access response. Parameter alpha_cA 3-bit cell specific value provided from a higher layer as a weight applied to a path loss in determining uplink transmission power (i.e., the higher this value, the greater the influence of the path loss on the uplink transmission power), and its value is limited according to the transmission type of the PUSCH. The parameter j indicates the transmission type of PUSCH. The parameter j is set to 0 for semi-static scheduling, 1 for dynamic scheduling and 2 for random access response. If there is no PUSCH transmission, M_PUSCHAnd Δ_TFIs not applied to equation 1.

In a mobile communication system supporting CA, there may be a serving cell in which PUSCH transmission does not occur and a serving cell in which PUSCH transmission occurs. In addition, the PH of the serving cell can be reported in another serving cell. In a mobile communication system supporting CA, when there is a need to report PHs of a plurality of serving cells, a UE can transmit the PHs in a single PHR. Compared with the method of transmitting the PH alone, the method is advantageous to reduce signaling overhead, and the eNB can obtain the PH of the carrier on which the PUSCH is not transmitted.

Fig. 5 is a diagram illustrating a PH report according to an exemplary embodiment of the present invention.

referring to fig. 5, a diagram illustrates two serving cells CC1 and CC2 transmitting PHs of the two serving cells. In duration 505, where PUSCH transmission occurs in CC1 but no PUSCH transmission occurs in CC2, the UE may transmit MAC PDU 510 containing CC1PH515 and CC2PH 520. Further, in a duration 525 in which PUSCH transmission occurs in CC2 but no PUSCH transmission occurs in CC1, the UE may transmit MAC PDU 530 including CC1PH 535 and CC2PH 540.

The exemplary extended PHR includes PHs of a plurality of carriers, and can selectively include each PH. Therefore, the length of the extended PHR varies depending on the situation. By introducing a new PHR format in addition to the legacy PHR format, a new area Identifier (LCID) is defined to identify the extended PHR for discrimination purposes. Since the length of the extended PHR is variable, a parameter L indicating the length of the extended PHR must be added. The Type 2(Type 2) PH may be included depending on whether PUSCH and PUCCH are simultaneously transmitted in a primary cell (PCell). The extended PHR also includes a PH of an activated Serving cell (SCell). Since the size of the extended PHR varies according to circumstances, a parameter L indicating the length of the extended PHR is inserted into the sub-header. Unlike PCell, SCell does not support simultaneous transmission of PUSCH and PUCCH, and Type2PH for SCell does not exist. The PHs of the respective carriers are arranged in order of Type2PH — > Type 1(Type1) PH — > PH of PCell, of activated scells, in ascending order of SCell index. Considering the fact that Type2PH exists only for PCell and can be correctly interpreted with Type1PH, the PH of PCell may be arranged at the beginning. Here, Type2PH is used when PUSCH and PUCCH are simultaneously transmitted. When receiving the extended PHR, the reception apparatus may acquire information on PHs for PUSCH transmission and PHs for PUCCH transmission in PCell based on Type2PH and Type1PH and process the same Type of PHs, i.e., Type1PH, at a time to reduce processing overhead.

While there is no true PUSCH transmission, the eNB may trigger the PHR in order to obtain path loss information on a particular uplink carrier. If PHR is triggered for a specific SCell, the UE determines a PH calculation rule according to whether there is a PUSCH transmission in the corresponding SCell. If there is a PUSCH transmission in the serving cell, the UE calculates the PH according to the related art method using equation 1. If there is no PUSCH transmission in the serving cell, this means that no transmission resources are allocated and which M should be used_PUSCHAnd Δ_TFIs unclear so that eDevices of NB and UE use the same M_PUSCHand Δ_TFCalculate and interpret PH. This problem can be solved by utilizing a fixed transport format (e.g., amount of transmission resources and MCS level) agreed between the UE and the NB for PH calculation without PUSCH transmission. Assume that the reference transport format is a combination of one (1) Resource Block (RB) and the lowest MCS level, M_PUSCHAnd Δ_TFBoth are set to 0 and this is the same meaning as omitting these parameters in equation 1. Since there is no real data transmission in the corresponding serving cell, P_CMAX,c(i) Is absent. Thus, P_CMAX,c(i) Must be determined. For such virtual transmission, a virtual P is defined and employed_CMAX,c(i) In that respect The maximum allowed UE output power P may be used_EMAXAnd nominal UE power P_PowerClassto determine P_CMAX,c(i) in that respect For example, P_CMAX,c(i) can be determined as equation 2:

Equation 2

P_CMAX，c＝min{P_EMAX，P_PowerClass}

P_CMAXHaving P_{CMAX_L}≤P_CMAX≤P_PowerClassThe relationship (2) of (c). Here, if zero power back-off is considered, P is_{CMAX_L}＝P_{CMAX_H}And thus P_CMAX＝P_{CMAX_H}. At this time, P_CMAXIs P_PowerClassAnd P_EMAXThe smallest one. P_EMAXIs the maximum allowed UE transmission power, cell-specific, and P_PowerClassIs the maximum allowed power specific to the UE.

As described above, the LTE-a mobile communication system allows simultaneous transmission of PUSCH and PUCCH. Different PH information must be used for transmission of only PUSCH and simultaneous transmission of PUSCH and PUCCH.

Fig. 6 is a diagram illustrating resource allocation for transmission of only a PUSCH and simultaneous transmission of a PUSCH and a PUCCH according to an exemplary embodiment of the present invention. In fig. 6, the left diagram shows resources fully allocated to PUSCH 605, and the right diagram shows resources allocated to PUSCH 615 and PUCCH 610. Here, the horizontal axis is a time axis, and the vertical axis is a frequency axis.

Referring to fig. 6, when both PUSCH and PUCCH are transmitted, transmission power allocated for PUSCH and PUCCH should be excluded from maximum transmission power of the UE to calculate PH. In case of simultaneous transmission of PUSCH and PUCCH, the eNB informs the UE before transmission of the PUSCH configuration. In order to provide PH for transmission of only PUSCH and PH for simultaneous transmission of PUSCH and PUCCH, Type1PH and Type2PH are used. Type1PH is defined as P_CMAX-P_PUSCH. Here, P_PUSCHIndicates the transmission power allocated to the PUSCH. Type2PH is defined as P_CMAX-P_PUSCH-P_PUCCH. Here, P_PUCCHindicates transmission power allocated to the PUCCH. If simultaneous transmission of PUSCH and PUCCH is not indicated in the PUCCH configuration, only Type1PH is used. Otherwise, both Type1PH and Type2PH are used. Type2PH is used for PCell in CA system but not for SCell. If simultaneous transmission of PUSCH and PUCCH is indicated in PUCCH configuration, both Type1PH and Type2PH for PCell are included in PHR.

As described above, the eNB can trigger the PHR in order to obtain path loss information on a specific uplink carrier even in case no PUSCH (or PUCCH) transmission is scheduled. Although simultaneous transmission of PUSCH and PUCCH is indicated in the PUCCH configuration, either or both of PUSCH and PUCCH may not be transmitted for a specific duration. In a CA system having a plurality of serving cells, if at least one serving cell satisfies a PHR trigger condition, PHs of all activated cells configuring an uplink carrier are generated and reported to an eNB. Here, the uplink channel of the PCell may be in one of four states:

PUSCH and PUCCH transmission states

PUSCH-Only Transmission State

PUCCH-only transmission state

Non-uplink transmission state

It is necessary to calculate Type1PH and Type2PH depending on the uplink channel transmission state. Exemplary embodiments of the present invention provide a method of calculating a PH depending on an uplink transmission state as follows. The following descriptionIn (1), the term "true P_CMAX"denotes P determined by considering true uplink transmission_CMAXAnd the term "reference P_CMAX"denotes P determined assuming that backoff parameters such as Maximum Power Reduction (MPR) and Additional MPR (a-MPR) are set to 0_CMAX。

Case 1) PUSCH and PUCCH Transmission states

Type1PH ═ true P_CMAXTrue PUSCH Power

Type2PH ═ true P_CMAXTrue PUSCH Power-true PUCCH Power

Case 2) PUSCH-Only Transmission State

Type1PH ═ true P_CMAXTrue PUSCH Power

type2PH ═ true P_CMAXtrue PUSCH Power-virtual PUCCH Power

Case 3) PUCCH-only transmission state

Type1PH ═ P of reference_CMAXVirtual PUSCH Power

Type2PH ═ true P_CMAXVirtual PUSCH Power-true PUCCH Power

case 4) non-uplink transmission state

Type1PH ═ P of reference_CMAXVirtual PUSCH Power

Type2PH ═ P of reference_CMAX-virtual PUSCH power-virtual PUCCH power

Here, the true PUSCH power and the true PUCCH power represent transmission powers required for respective true PUSCH and PUCCH transmissions in the PCell, and the virtual PUSCH power and the virtual PUCCH power represent transmission powers determined using a preset transmission format, regardless of no PUSCH and PUCCH transmission in the PCell. True P obtained by considering true uplink transmission in case there is true uplink transmission in PCell_CMAXIs configured as P_CMAX. In the special case of transmission PUCCH only, P of reference is used_CMAXto calculate Type1PH, and use true P_CMAXTo calculate Type2 PH. This is because PUSCH transmission may be performed anywhere within a cell band depending on scheduling decisions, while PUCCH transmission may be performed in a limited region of the cell band (i.e., both edges of the cell band). If true P is used_CMAXcalculating Type1PH without considering transmitting only PUCCH, it is not necessary to apply Δ T_CThis results in distortion (distortion) of Type1 PH. Since the reverse is not true (i.e., true P is utilized although only PUSCH is transmitted_CMAXtype2PH is calculated, but no distortion occurs in Type2PH calculation), so true P is utilized in case 2)_CMAXboth Type1PH and Type2PH are calculated.

determining P by considering PUSCH and/or PUCCH transmissions_CMAXP is determined according to the method specified in the 3GPP TS36.101 standard_CMAX. In more detail, when P is determined_CMAXThe parameters MPR, a-MPR, Power Management-Maximum Power Reduction (P-MPR) and Δ T are determined by considering modulation and transmission bandwidth, Adjacent Channel Leakage Ratio (ACLR) and spectral emission requirements in the corresponding Channel_C. UE determines P_CMAXWithin the following ranges.

P_{CMAX_L}≤P_CMAX≤P_{CMAX_H}

Here, the first and second liquid crystal display panels are,

P_{CMAX_L}＝MIN{P_EMAX-T_C,P_PowerClass-MAX(MPR+A-MPR,P-MPR)-T_C}

P_{CMAX_H}＝MIN{P_EMAX,P_PowerClass}

P_CMAXIs cell-specific maximum allowed transmission power, and P_PowerClassIs the maximum allowed power specific to the UE.

The MPR is determined based on a modulation scheme and a transmission bandwidth of a channel.

The a-MPR is determined taking into account ACLR and spectral emission requirements.

The P-MPR is a value for power management, and TC is an operating band edge transmission power relaxation value.

reference P_CMAXRepresenting a virtual P obtained by considering the zero power backoff and the above condition_CMAX,c(i) In that respect If there is no PUSCH and PUCCH transmission, this means that transmission power is not allocated to the corresponding channel, and instead preset transmission formats called virtual PUSCH and virtual PUCCH are applied according to exemplary embodiments of the present invention.

Fig. 7 is a flowchart illustrating a PHR transmission procedure according to an exemplary embodiment of the present invention.

Referring to fig. 7, the UE configures an extended PHR (i.e., REL-10PHR) in step 705. In step 710, the PHR trigger condition is satisfied. That is, if a forbidden PHR timer (prohibitphr) has expired and if a path loss displacement (dispalcement) on at least one downlink carrier associated with a corresponding uplink carrier is greater than a DL path loss variation (dlpathlosssenge), PHR is triggered for all activated cells configuring the uplink carrier. The UE may trigger the PHR periodically and if a new uplink transmission occurs after the REL-10PHR configuration, the UE triggers the PHR for all activated serving cells configured with uplink carriers. In step 715, the UE determines P of PCell according to the above method_CMAX. At this time, 4 transmission states are considered. In step 720, the UE uses P_CMAXand PUSCH and PUCCH transmission power to determine Type1PH and Type2PH of the PCell. In step 725, the UE determines P of the activated SCell_CMAX. In step 730, the UE determines Type1PH of the SCell. The UE applies true P if there is any uplink transmission in the corresponding SCell_CMAXDetermining Type1PH with true PUSCH power, otherwise, applying reference P_CMAXAnd virtual PUSCH power to determine Type1 PH. The UE configures a PHR including a PH in step 735, and transmits the configured PHR in step 740.

Fig. 8 is a block diagram illustrating a UE according to an exemplary embodiment of the present invention.

Referring to fig. 8, the UE includes a transceiver 805, a PH calculator 815, a controller 810, a multiplexer/demultiplexer 820, a control message processor 835, and various higher layer devices 825 and 830.

The transceiver 805 receives data and control signals on a downlink carrier and transmits data and control signals on an uplink carrier. In the case where multiple carriers are aggregated, the transceiver 805 can transmit/receive data and control signals over the multiple carriers.

The controller 810 controls the multiplexer/demultiplexer 820 to generate a MAC PDU according to a control signal (e.g., scheduling information in uplink) received through the transceiver 805. The controller detects a PHR trigger. If a PHR trigger is detected, the controller 810 controls the PH calculator 815 to determine PH. Whether to trigger the PHR may be determined by verifying the PHR parameter provided by the control message processor 835. In case that PHs of a plurality of uplink carriers are configured into the PHR, the controller 810 controls the multiplexer/demultiplexer 820 to place an indicator, which indicates that the PH of each carrier is according to true P, in the MAC PDU_CMAXOr virtual P_CMAXAnd (4) obtaining the product. The controller 810 generates a PHR using the PH provided by the PH calculator 815 and transmits the PHR to the multiplexer/demultiplexer 820. The PH calculator 815 determines PH according to a control signal from the controller 810 and transmits the PH to the controller 810. In case that multiple carriers are aggregated, the PH calculator 815 may determine the PH of each carrier, in particular using a virtual P for the carrier with PUSCH transmission_CMAXThe pH was determined.

The multiplexer/demultiplexer 820 multiplexes data from the higher layer devices 825 and 830 and/or the control message processor 835, and demultiplexes data received through the transceiver 805 to the higher layer devices 825 and 830 and/or the control message processor 835.

Control message processor 835 processes control messages transmitted over the network and takes necessary actions. The control message processor 835 forwards the PHR parameter carried in the control message to the controller 810 or forwards information on the newly activated carrier to the transceiver 805 in order to set the carrier. Higher layer devices 825 and 830 may be implemented for respective services to deliver data generated by user services such as File Transfer Protocol (FTP) and VoIP to multiplexer/demultiplexer 820 or to process and deliver data from multiplexer/demultiplexer 820 to higher layer service applications.

Although not shown, the base station apparatus according to an exemplary embodiment of the present invention may include a transceiver, a controller, and a scheduler. The transceiver receives the extended PHR transmitted by the UE. The controller analyzes the extended PHR to verify the PH of each serving cell. The scheduler allocates uplink resources according to the PH of each serving cell.

As described above, the PH calculation method and apparatus according to exemplary embodiments of the present invention can calculate the PH of an active serving cell by considering whether the active serving cell has uplink transmission data and/or uplink control signals to be transmitted, thereby more efficiently determining the PH of each active serving cell.

While the invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents.

Claims

1. A method for calculating a Power Headroom (PH) of a terminal in a wireless communication system, the method comprising:

Determining whether the terminal transmits a Physical Uplink Shared Channel (PUSCH) and a Physical Uplink Control Channel (PUCCH) in a subframe for a serving cell;

Determining a first maximum uplink transmission power for type1PH and a second maximum uplink transmission power for type2PH based on the cell-specific maximum allowed transmission power and the terminal-specific maximum allowed transmission power; and

Calculating type1PH based on the first maximum uplink transmission power and type2PH based on the second maximum uplink transmission power,

wherein the first maximum uplink transmission power is a reference maximum uplink transmission power with a backoff parameter of zero and the second maximum uplink transmission power is a true maximum uplink transmission power if the terminal transmits the PUCCH but not the PUSCH.

2. The method of claim 1, wherein if the terminal transmits PUSCH and PUCCH, the type2PH is calculated based on transmission power for PUSCH and transmission power for PUCCH.

3. The method of claim 1, wherein if the terminal transmits PUSCH without PUCCH, the type2PH is calculated based on transmission power for PUSCH and assumed transmission power for PUCCH.

4. The method of claim 1, wherein if the terminal does not transmit PUSCH, the type2PH is calculated based on an assumed transmission power for PUSCH.

5. The method of claim 1, wherein the first and second maximum uplink transmission powers are true maximum uplink transmission powers if the terminal transmits PUSCH and PUCCH or if the terminal transmits PUSCH without PUCCH, and,

Wherein the first maximum uplink transmission power and the second maximum uplink transmission power are reference maximum uplink transmission powers if the terminal does not transmit PUSCH and PUCCH.

6. the method of claim 1, wherein the backoff parameter comprises at least one of a Maximum Power Reduction (MPR) and an additional MPR (a-MPR).

7. A terminal for calculating a Power Headroom (PH) in a wireless communication system, the terminal comprising:

a transceiver configured to transmit and receive signals; and

A controller configured to:

Determining whether the terminal transmits a Physical Uplink Shared Channel (PUSCH) and a Physical Uplink Control Channel (PUCCH) in a subframe for a serving cell,

Determining a first maximum uplink transmission power for type1PH and a second maximum uplink transmission power for type2PH based on the cell-specific maximum allowed transmission power and the terminal-specific maximum allowed transmission power, and

Calculating type1PH based on the first maximum uplink transmission power, and calculating type2PH based on the second maximum uplink transmission power,

8. The terminal of claim 7, wherein if the terminal transmits the PUSCH and the PUCCH, the type2PH is calculated based on a transmission power for the PUSCH and a transmission power for the PUCCH.

9. The terminal of claim 7, wherein if the terminal transmits the PUSCH without transmitting the PUCCH, the type2PH is calculated based on a transmission power for the PUSCH and a transmission power for the PUCCH assumed.

10. The terminal of claim 7, wherein if the terminal does not transmit the PUSCH, the type2PH is calculated based on an assumed transmission power for the PUSCH.

11. The terminal according to claim 7, wherein the first and second maximum uplink transmission powers are true maximum uplink transmission powers if the terminal transmits PUSCH and PUCCH or if the terminal transmits PUSCH without PUCCH, and,

12. The terminal of claim 7, wherein the backoff parameter comprises at least one of a Maximum Power Reduction (MPR) and an additional MPR (a-MPR).

13. A method for receiving a Power Headroom (PH) by a base station in a wireless communication system, the method comprising:

receiving an extended PH report from a terminal; and

Identifying a power headroom for a serving cell based on the extended PH report,

Wherein a first maximum uplink transmission power for a type1 Power Headroom (PH) and a second maximum uplink transmission power for a type2PH are determined based on the cell-specific maximum allowed transmission power and the terminal-specific maximum allowed transmission power,

Wherein type1PH is calculated based on a first maximum uplink transmission power, and type2PH is calculated based on a second maximum uplink transmission power, and,

14. The method of claim 13, wherein if the terminal transmits PUSCH and PUCCH, the type2PH is calculated based on a transmission power for PUSCH and a transmission power for PUCCH,

Wherein if the terminal transmits PUSCH without transmitting PUCCH, the type2PH is calculated based on a transmission power for PUSCH and a transmission power for PUCCH assumed, and

Wherein if the terminal does not transmit the PUSCH, the type2PH is calculated based on an assumed transmission power for the PUSCH.

15. The method of claim 13, wherein the first and second maximum uplink transmission powers are true maximum uplink transmission powers if the terminal transmits PUSCH and PUCCH or if the terminal transmits PUSCH without PUCCH, and,

16. The method of claim 13, wherein the backoff parameter comprises at least one of a Maximum Power Reduction (MPR) and an additional MPR (a-MPR).

17. A base station for receiving a Power Headroom (PH) in a wireless communication system, the base station comprising:

a transceiver configured to transmit and receive signals; and

a controller configured to:

Receiving an extended PH report from a terminal, an

Wherein the first maximum uplink transmission power for the type1PH and the second maximum uplink transmission power for the type2PH are determined based on the cell-specific maximum allowed transmission power and the terminal-specific maximum allowed transmission power,

18. The base station according to claim 17, wherein if the terminal transmits PUSCH and PUCCH, the type2PH is calculated based on a transmission power for PUSCH and a transmission power for PUCCH,

19. The base station according to claim 17, wherein the first and second maximum uplink transmission powers are true maximum uplink transmission powers if the terminal transmits PUSCH and PUCCH or if the terminal transmits PUSCH without PUCCH, and,

20. The base station of claim 17, wherein the backoff parameter comprises at least one of a Maximum Power Reduction (MPR) and an additional MPR (a-MPR).